Process for the reduction of nitro derivatives to amines

Abstract

Disclosed is a novel process for the reduction of nitro groups to amino derivatives, based on the use of trichlorosilane and an organic base, which is efficient from the chemical standpoint and of wide general applicability.

The invention claimed is: 
     
       1. Process for the reduction to amine of a nitro group present in an aliphatic, cycloaliphatic, aromatic or heteroaromatic compound, wherein said compound is reacted with trichlorosilane in the presence of a base. 
     
     
       2. Process according to  claim 1 , wherein a trichlorosilane to nitro group molar ratio ranging from 1 to 5 is used. 
     
     
       3. Process according to  claim 2 , wherein the trichlorosilane to nitro group molar ratio is 3.5. 
     
     
       4. Process according to  claim 1 , wherein said base is an organic base selected from the group consisting of secondary or tertiary amines. 
     
     
       5. Process according to  claim 4 , wherein the organic base is triethylamine or diisopropylethylamine. 
     
     
       6. Process according to  claim 4 , wherein a base to nitro group molar ratio ranging from 1 to 10 is used. 
     
     
       7. Process according to  claim 6 , wherein the base to nitro group molar ratio is 5. 
     
     
       8. Process according to  claim 1 , wherein the nitro group is present in an aromatic or heteroaromatic compound and the base is triethylamine or diisopropylethylamine. 
     
     
       9. Process according to  claim 1 , wherein the nitro group is present in an aliphatic or cycloaliphatic compound and the base is diisopropylethylamine. 
     
     
       10. Process according to  claim 1 , wherein the nitro group is present in an alkene. 
     
     
       11. Process according to  claim 1 , wherein the nitro group is present in a compound which contains at least one functional group selected from the group consisting of a double or triple carbon-carbon bond; a carbonyl group; halogen; C1-C4 hydroxyalkyl; allyl ether; C7-C18 arylalkyl ether; C1-C4 acylamino; nitrile; carboxyl; a carboxylic or thio-carboxylic ester selected from the group consisting of C1-C4 alkyl ester, C6-C14 aryl ester or C7-C18 arylalkyl ester. 
     
     
       12. Process according to  claim 11 , wherein the functional group is selected from the group consisting of acetyl, formyl, hydroxymethyl, benzyl ether, acetylamino, benzyl ester. 
     
     
       13. Process according to  claim 1 , wherein at the end of the reduction of the nitro group to amine, the compound is not isolated.